* Makefile.am: adding repeated parsing and validating tests
* SAX2.c parser.c tree.c include/libxml/parser.h: make the new
  DOM tree building interfaces use the dictionary from the
  parsing context to build the element and attributes names
  as well as formatting spaces and short text nodes
* include/libxml/dict.h dict.c: added some reference counting
  for xmlDictPtr because they can be shared by documents and
  a parser context.
* xmlreader.c: a bit of cleanup, remove the specific tree freeing
  functions and use the standard ones now.
* xmllint.c: add --nodict
* python/libxml.c: fix a stupid bug so that ns() works on
  attribute nodes.
Daniel